ANSYS codes included to assist with FEM analysis of magnetic flux devices

This text investigates the materials science and physics of energy harvesting, with a focus on system configuration and efficient performance. It presents the mathematical theory of materials, electrical conductivity, and device design for vibration-based harvesters, thermoelectrics, photovoltaics, wind-energy turbines, and hybrids thereof. Examples include piezoelectrics in wind turbines, as well as approaches using shape-memory alloys, thermomagnetics, and electrostatic generation. Information is provided on testing, characterization, and modeling of EH systems, with extensive equations analyzing materials and energy flow. Circuitry, batteries, and capacitors are also covered. An appendix includes ANSYS codes for finite element analysis of magnetic flux devices.

Educators will find this book highly relevant for courses in energy harvesting, sustainable and renewable energy, thermal energy, wind energy, solar energy, magnetic energy, and vibrations.
Materials scientists, energy harvesting developers, and renewable energy specialists will find the book to be a key resource.

FROM THE PREFACE

In this book, we provide the fundamental concepts required to design, model, fabricate, and characterize efficient and cost-effective energy harvesters. Various types of harvester designs are discussed that harvest energy from vibration, thermal gradients, solar, and wind. The volume is arranged in a systematic manner explaining all the basic principles with essential mathematical and physical models. Wherever possible, supporting examples are included that provide a summary of ongoing and past developments. The exhaustive content on each of the sub-topics in this textbook gives students and researchers a strong foundation for understanding the design and operation of energy harvesters. Educators will find this book highly relevant for classes on energy harvesting, sustainable and renewable energy, thermal energy, wind energy, solar energy, magnetic energy, and vibrations.

The most popular renewable energy sources are wind and sun, biomass and flowing water are usually also subsumed in this category. The latter receive less attention when discussing widely varying supply and associated challenges. Only in extreme weather and season situations their supply might be limited: In very hot summers with long dry periods the growth of plants used in biomass-fueled installation may be a problem, and low water levels may limit power generation in power plants in rivers. Fluctuations on wide time scales are the rule with sun and wind. This applies to some other energy sources, too. They are less popular but also important enough to merit researcher’s attention. The present book provides a timely collection of chapters dedicated to them, in particular to vibration energy and thermal energy. Photovoltaic and wind energy harvesting are treated also. Even the term “energy harvesting”, which may sound somewhat strange to some electrochemists, becomes rather natural, almost familiar, to the reader after finishing this book.

Starting with an overview the reader is made familiar with those forms of energy available for harvesting: Vibrational, thermal, light and wind. Terminology is a bit confusing and non-systematic. Photovoltaic is presumably not a form of energy but a mode of conversion, and even wind is only a typical feature of daily weather and no form of energy. Accepting these minor imprecision’s in daily discussion is hard to avoid, in the present text it does not result in confusion. At the end of chapter one an extensive section is dedicated to electric energy conversion and storage. The wide fluctuations of supply are a characteristic of all these forms of energy, and consequently electric means of converting the supply into a stream of electric current compatible with the demand of a device as well as storing excess energy for demand in times of no supply are of major importance. The latter is good news for the electrochemist dealing in batteries and supercapacitors. This section gives a short overview, just enough to demonstrate the major importance of electrochemical energy storage and conversion.

The following chapters are treating the various means of harvesting mechanical, thermal, solar and wind energy. Converters of mechanical into electric energy based on inductive, piezoelectric and magnetostrictive principles are handled in separate chapters. Thermoelectric converters (for both modes of operation heat into electric energy and vice versa) are discussed in great detail; the same applies to photovoltaic’s in chapter six. The chapter on wind energy conversion seems to be a bit short, but major parts have been covered in the somewhat unbalanced introductory chapter already. In a final chapter further options including shape memory alloy heat engines, thermomagnetic and electrostatic harvesting are briefly introduced.

The book is a helpful source for any reader interested in more details of the use of renewable energies large and small. The electrochemist will benefit from a better knowledge of those devices feeding his batteries and supercaps. All will learn more about energy sources and their utilization beyond the carbon and nuclear age.

Dr. Rudolf Holze, Chemnitz University of Technology and Saint Petersburg State University, Institute of Chemistry

Michael Lublow – October 10, 2018:

Energy Harvesting by R. A. Kishore, A. M. C. Wu, A. Kumar, and S. Priya from DEStech Publications, meets the demand for an up-to-date edition, likewise suitable for the interested student, the active researcher and the university lecture in a very convincing way. What type of energy harvesting can be applied? What is the physics, what is the mathematics behind it? Which sort of materials can be used to convert energy from one form to another? How do basic device designs look like? All of these questions and much more are addressed in this book devised by some of the leading experts in this field and supported by a plenty of instructive graphics, schematics, and photos of actual prototypes.

In the introductory part, Overview of Energy Harvesting, we are introduced to the various methods by which energy can be extracted from the environment: vibrational, thermoelectric, photovoltaic and wind energy harvesting. This chapter presents some basic mathematical treatment, quantitative assessment of the available energy and provides first examples of application. With a look on electric circuitry and energy storage elements the chapter completes and leads to the following paragraphs with in-depth descriptions. The reader is thereby comprehensively guided along the essential cornerstones of energy harvesting as outlined in the introduction.

Owing to the importance of the conversion process of mechanical to electrical energy, this next section fills approximately one hundred pages and elaborates on the principles of electromagnetic (inductive), piezoelectric and magnetostrictive techniques. Further energy harvesting concepts such as thermoelectric and photovoltaic energy harvesting are covered in the subsequent two chapters, and the authors succeed to impart sufficient knowledge on semiconductor physics to make the underlying physics comprehendible.

Browsing through the following chapter on wind energy harvesting, the reader should not be fooled by thinking on high-rise megawatt systems decorating the horizon. In fact, small- and micro-scale wind turbines with rotor diameters down to 10 cm fit in well in the conceptual strategies of energy harvesting for low-energy devices. The background theory here is less demanding, and only geometrical and engineering considerations require the reader`s attention.

Finally, the authors provide a summary on less established techniques such as the shape memory alloy heat engine, thermomagnetic and electrostatic energy harvesting. Throughout the text, the relevant physics and mathematics, necessary for the understanding of the respective subject, is outlined and mostly does not require deeper knowledge than an undergraduate has already on hand after some semesters. At one point or the other, the curious reader may feel the need for further reference work to achieve deeper insight on how some mathematical formulas are derived, as e.g. in electromagnetics, or to understand the specifications of certain types of solar cells. In general, however, the included background theory is presented in a precise, clear and fully sufficient way to focus just on the essentials.

Furthermore, for more complex problems the authors employed numerical simulations, using ANSYS, and provide some example coding in the appendix. They provide, wherever possible, prototype designs which illustrate important working examples. One final word on the excellent design of the chapters: the authors decided not only to retrospect on the history of the respective technologies for each individual topic but also to include commentary on the state-of-the-art and on envisaged future developments. This conceptual structure makes the book particularly worth reading and entertaining, and the less experienced reader will benefit from this holistic expert view. Congratulation for this excellent edition!

Michael Lublow, Editor-in-Chief of Energy Harvesting and Systems, De Gruyter